I bought this bag for fall camping. The temp at nites were at 51-54 degrees and my grandson and I were quite warm in the bags. The outside of the bag is smooth nylon and the inner is flannel. I love the way the flannel lining rolls over to the top outside the bag. a nice touch! The zippers are pretty good haven't got one stuck as of yet. The only thing I could complain about is the two strings that keep it rolled up are just that two strings (come on coleman) two separate one inch straps woulda been better. All in all I would buy again. Oh and the size is only 36 inches wide not 39 as is stated on the bags tag! I have emailed Coleman about this but no answer as of yet??????